Piano Roll is a sequencer for iOS, and the first in our Atom series of modular sequencer plugins. Record, replay, loop and manipulate MIDI notes anywhere.

The MIDI audio unit can be loaded in compatible hosts (AUM, ApeMatrix, Audiobus, BeatMaker 3, Cubasis 2, etc.). Make sure your host is capable of loading, transmitting to, and receiving MIDI from audio unit MIDI plugins.

It’s intended to augment existing MIDI processing capabilities, or in scenarios where a host doesn’t provide sequencing functionality out of the box.


1) Loop record
Grow your ideas over any number of bars. Overdub drum loops, layer complex melodies, or even record an entire track. Arm recording in multiple instances, in the background, receiving from hardware or even other audio units. Piano Roll is always sample accurately synced with the host.

2) Step input
Quickly create sequences. Insert notes respecting grid length, and resize them to any duration. Layer chords in one operation. Just send the notes, Piano Roll takes care of the rest.

3) Extensive editing tools
All the standard editing tools you are used to are implemented, pen for entering notes at any length, brush for painting continual notes at grid size and scissors for slicing.

Advanced tools allow you to be productive. Grow notes backwards or forwards. Group notes with additive selection. Select rows or chords in one operation. Time and pitch flip. Velocity editing is precise and unobtrusive. With Piano Roll, anything you need is a tap, hold, or swipe away.

3) Non destructive quantize
Quantised or not? You decide when, and how much! Enable full quantisation beforehand with grid snapping. Turn it back off, or adjust the strength afterwards on an already recorded sequence. Choose the quantisation percentage for note starts, note ends and even note durations. In Piano Roll, you have full control over timing precision.

4) Dynamic stretching
Stretch a clip from 4 bars to 8. Fix the note lengths or extend them in harmony. In Piano Roll, your sequences are elastic.

5) Advanced time signatures
Does 4/4 sound boring to you? Create complex polyrhythms by choosing any timing. From 3/8 to 11/8. From 2/1 to 17/16. Piano Roll lets you invent your own rhythm.

6) Advanced tempo settings
Negative BPM? No problem. Pick a tempo for every clip and play backwards or forwards. Multiply host tempo or choose something arbitrary, all with extreme accuracy. Piano Roll gives you control over tempo like never before.

7) Scales
Never go outside a scale, or go chromatic and add spice to the melody. With scale overlays, your music isn’t forced to sound in a predetermined way, and you aren’t forced to be a music theory genius to sound the way you want. Piano Roll gives you the ability to decide in which key to be and when.

8) Visibility layers
Aid composition by overlaying other clips from other plugin instances over the one you’re editing. Make sure your chords are in harmony with the melody, visually. Piano Roll roll helps you focus where you need, when you need it.

10) State saving
Your sequences are saved alongside the project you already work with. And they’re loaded back automatically when opening up a project. Clips can be saved as host presets. Piano Roll is in perfect harmony with the host you already use.

What’s New

Version 1.0.1

- Fixed rendering issues on iOS 11
- Layout improvements for small screen sizes
- Note entry improvements for right-to-left gestures
- History stack improvements for flip operations
- Various other small quality of life improvements

Ratings and Reviews

4.2 out of 5
69 Ratings

69 Ratings

wareismike ,

Landmark Addition to iOS Music Making!

At last! A modular way to easily record, edit, and loop midi in iOS. If you’re at all into creating on the fly in hosts like AudioBus, AUM, and ApeMatrix, which have no built-in midi recording and editing, this changes everything!

Not only that, but Atom Piano Roll is about as perfect an implementation as you will ever find on iOS. It’s not as feature complete as it will be in the coming months, but it has the essentials, and it has them flawlessly executed.

Likewise, if you normally use one or more timeline based DAWs, but aren’t happy with their midi editing, you owe it to yourself to check this out. I know that except for two apps, I will be using Atom as a replacement for the piano roll editors that I just don’t get along with.

I could not be happier with this purchase!!

tesserat ,


I had some initial hiccups but I stuck with it and it’s pretty smooth now. Makes good use of touch gestures. It seems to encourage you more to play something in to get started whereas I am looking to get something drawn in quickly to get started. It’s a little hard to navigate around the octaves and measures, especially when there’s no notes recorded in there yet.

Anyway, people who like playing stuff in will like it more I think. Still giving four stars because it’s a very well done app and really takes AUM to a new level for many users. Just not quite tailored to my workflow.

DB1983_ok ,

Really great potential & design... but no MIDI channel setting, 40 bar limit, and crashes.

Beautiful app, simple and well-designed. But it appears that there’s no way to change the MIDI output channel from Channel 1. This is a fundamental oversight for an AU plugin intended for making music in 2019. Hopefully this can be added, but as-is, this is a serious limitation that I’m a bit surprised is an issue. There’s also an arbitrary 40-bar limit.

I’ve also found that if you leave it open long enough, all instances of the plugin will crash. The quest for a decent standalone piano roll AU continues...


Victor Porof
14.3 MB

Requires iOS 11.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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